Bring a large pot of water to a boil for the pasta. When the water comes to a boil, add salt and cook the pasta al dente.

While the pasta cooks, preheat a large, deep skillet over moderate heat. Add the EVOO and bacon and cook until the bacon crisps, about 3 minutes. To the bacon add the garlic, onions, salt, pepper, and crushed red pepper flakes and cook, stirring frequently, for 5 minutes, or until the onions are lightly caramelized. Add the chopped Swiss chard, toss to coat, and wilt the chard down. Turn the heat up to high and add the chicken stock and a couple of ladles, about a cup, of the starchy boiling water from the cooking pasta. When the liquid comes to a boil, reduce the heat and simmer for 6 to 7 minutes.

In a small bowl, combine the ricotta with the lemon zest and season with salt and pepper. Place 1/4 cup of the ricotta mixture in the bottom of each of 4 pasta bowls and reserve.

Add the lemon juice to the Swiss chard. Drain the pasta well and toss with the greens for a minute or so to let the juices absorb into the pasta. Turn the heat off and add the grated Parmigiano cheese to the pasta and greens and continue to toss to distribute. Serve the pasta immediately, dishing it up on top of the ricotta cheese. Stir the lemony ricotta up in your bowl to mix with the pasta.